Gauge lens with embedded anti-fog film and method of making the same

ABSTRACT

The gauge lens with anti-fog film includes a substantially planar transparent lens substrate having an outer surface and an inner surface and a thin film possessing anti-fog properties adjacent and substantially covering the inner surface of the lens substrate to provide a low angle of contact for water and moisture. The anti-fog film is bonded to the lens substrate during the molding process that produces the lens substrate shape. The anti-fog film comprises a hydrophilic material or is coated with a hydrophilic coating. In addition to the anti-fog film, in another embodiment, the outer surface of the lens substrate has a hard coat film adjacent and substantially covering the outer surface of said lens. The materials for the lens substrate, anti-fog film, and hard coat film are selected based on the application, performance, and stability of the gauge lens in the environment that it is operated.

RELATED APPLICATIONS

This application is a division of application Ser. No. 12/314,463 filedDec. 11, 2008 which is a divisional of application Ser. No. 11/114,156filed Apr. 26, 2005 now abandoned.

FIELD OF THE INVENTION

This invention relates broadly to the field of rendering and maintaininga surface of a substrate highly hydrophilic, and more particularlyrelates to a gauge lens having an embedded film with anti-fogproperties.

PROBLEM

It is a problem in the field of sealed gauges, such as instruments,controls, instrument clusters, instrument panels, and the like, toalleviate moisture condensation from accumulating on the inner surfaceof the lens of these gauges when they are subjected to certainconditions. These gauges are typically formed of some type of acrylicand assembled in environments and factories that have some relativehumidity, thus when they are sealed they typically contain the samerelative humidity that was present during the manufacturing process foreach particular gauge. In addition, when these gauges are subjected tocertain environmental conditions, such as rain and cold weather, themoisture contained within the gauge forms condensation on the innersurface of the acrylic lens of that gauge and obscures or completelyobstructs the view of a user to the information displayed by that gaugelens. Gauge lenses that possess a coating or are made out of a materialthat reduces the occurrence of moisture condensation formation duringthese conditions are commonly known as having anti-fog properties.

Additionally, acrylic lens provide good UV-stability relative to many ofthe anti-fog coatings and films presently used with other lensmaterials. Some attempts have been made to utilize lens substrateswholly composed of anti-fog material. However, these anti-fog materialsdo not typically provide good stability to UV exposure and tend toyellow and become brittle when exposed for prolonged periods of time toUV radiation, such as by repeated or constant exposure to the sun. Otherattempts have been made to add UV stabilizers to these anti-fogmaterials, but they still do not possess the UV stability of commonlyused acrylics. Moreover, many manufacturers of vehicles that utilizethese gauges require that the lens undergo extreme UV exposure testing.

In some applications, such as with automotive headlamps, the lenssubstrate is comprised of polycarbonate, that is prone to yellowing.Typically, to address this problem, the polycarbonate lens substrate iscovered with a UV stable hard coat material to prevent yellowing of thepolycarbonate lens substrate. To apply this hard coating the lenssubstrate material is usually spray or dip coated, which produces flowlines. Another disadvantage of dip or spray coating is that impuritiesthat are part of the liquid coating become dried impurities of theanti-fog film once it dries. Some of these applications require 24 to 48hours drying or curing times which exposes the coated lens to furtherairborne contaminates and impurities, such as dust. Other attempts havebeen made to alleviate or reduce moisture condensation from forming onthe inner surface of these gauge lenses.

In one such attempt, an organic hard coat scuff-resistant layer isdeposited on a release film and then pressed to one side of a flat sheetof polycarbonate and a hydrophilic organic hard coat anti-fog layer isdeposited on another release film and pressed to the other side of theflat sheet of polycarbonate. The polycarbonate combination is thentreated by ultraviolet (UV) radiation to cure the two coatings and therelease films are then removed. The polycarbonate is then slightly bentto form such articles as shields for helmets and the like. This processprovides for the polycarbonate lens substrate to be formed, deposited,and treated in flat sheets due to the nature of the process. The processdoes not provide for formed or shaped lenses for gauges, instruments,instrument clusters, or instrument panels. Further, the process as notedabove involves a substantial number of time-consuming process steps,including preparing the two coatings, applying them to their respectiverelease sheets, applying them to the polycarbonate substrate, pressingthem to the substrate, treating with UV radiation to cure the coatings,peeling the release films from the substrate, and possibly bending thefilm into a curved shape to produce a helmet visor, or the like.

Another approach to this problem has been to coat a surface of a lenssubstrate with a photocatalytic substance and then irradiating thecoating in the presence of water to render it hydrophilic. Over time thecoating loses its hydrophilic properties due to contaminants beingadsorbed on the surface of the hydroxyl groups of the coating surface.To restore the hydrophilicity, the coating is periodically subjected toadditional photoexcitation treatments.

Yet another approach applies a coating of silicone resin to the surfaceof a lens substrate. Some application techniques include spraying or dipcoating the lens substrate with the silicone resin. Coatings applied bydipping have only a poor-to-fair appearance, even if the parts arerotated during drippage. Additionally, coatings on vertical surfacestend to be thicker at the bottom than at the top, which distorts thelight rays emitting from the dial of the article through the lensmaterial. Flow lines may be visible around holes and openings, and beadsmay develop at the bottom edges of the lens substrate. This type ofprocess can be found in goggle manufacturing where the lens substrate isinjection molded and then coated or dipped with an anti-fog compound.This process then requires that the anti-fog compound be cured orhardened, which incurs further process expense and time.

Information relevant to attempts to address these problems can be foundin the U.S. Pat. Nos. 6,228,499 issued 8 May 2001 to Nakauchi, et al.;6,013,372 issued 11 Jan. 2000 to Hayakawa; 6,303,229 issued 16 Oct. 2001to Takahama et al.; 6,297,906 issued 2 Oct. 2001 to Allen et al.;6,165,256 issued 26 Dec. 2000 to Hayakawa et al.; and 6,830,785 issued14 Dec. 2001 to Hayakawa et al.

Therefore, there is a need for a gauge having an embedded lens withanti-fog properties that is durable, highly hydrophilic, stable toUV-radiation, free from flow lines caused by dip or spray coatingprocesses, affordable to manufacture, and that doesn't have or requirecomplex processes such as UV-radiation treatment, curing or hardeningsteps, repeated hydrophilicity treatments, or require adhesives.

SOLUTION

The above-described problems are solved and a technical advance isachieved in the art by the present gauge lens with embedded anti-fog.Preferably, the gauge lens comprises two layers of material, theanti-fog film and the lens substrate material, molded together toprovide the gauge lens with improved weatherability, durability, andanti-fog properties. The anti-fog properties of the anti-fog film aredue to its inherent chemical composition or to an anti-fog coating thatis applied to the film. The anti-fog film is adjacent to the lenssubstrate with the anti-fog side or coating of the film facing towardsthe interior of the gauge. Thus, when the gauge is exposed to conditionsthat promote moisture condensation, the gauge lens provides an anti-fogsurface for preventing the moisture from condensing onto the lens andobstructing or obscuring the view of a user.

The gauge lens with embedded anti-fog film provides a lens with improvedprotection from exposure to elements, such as sunlight, extremetemperatures and variances thereof, and physical stresses caused duringoperation of the gauge in the environment in which it is designed tooperate. The gauge lens provides for improved lamination quality betweenthe lens substrate and the anti-fog film for better Xenon arc weatherability tests. In addition, the present gauge lens design provides for agauge lens having anti-fog characteristics that is capable ofwithstanding thermal shock, and physical shocks, such as vibrationalshock while maintaining the bond between the lens substrate material andthe anti-fog film.

A manufacturing process that molds the lens substrate and anti-fog filmtogether during the process achieves these improved features.Preferably, the anti-fog film is placed in a mold prior to injecting thegauge lens substrate material into the lens. This process ensures astrong bond between the selected anti-fog film material and lenssubstrate material. In addition, due the anti-fog film being intermoldedwith the lens substrate at a molding temperature, impurities that arepresent in the mold or caused by handling the materials are vaporizedand thus are not part of the finished gauge lens product. The presentgauge lens also provides for a second film to be molded to the outerlayer of the lens substrate material for additional durability.

SUMMARY

The invention provides an anti-fog gauge lens, including a substantiallyplanar transparent lens substrate having an outer surface and an innersurface; and a film having a first surface and a second surface, thefirst surface of the film is adjacent and substantially covering theinner surface of the lens, and the second surface having hydrophilicproperties for preventing moisture condensation from forming on thesecond surface of the film. Preferably, the first surface of the film isbonded to the inner surface of the lens during the molding process ofthe lens. Preferably, the lens substrate comprises a thermoplasticmaterial. Preferably, the lens substrate comprises a polymer selectedfrom the group consisting of polyvinyl chloride, nylon, fluorocarbons,linear polyethylene, polyethylenes, polyethylene terephthalate,polyurethane prepolymer, polyesters, polycarbonates, polystyrene,polypropylene, cellulosic resins, acrylic resins, acrylates, methylmethacrylate, polymethyl-methacrylate, epoxides, epoxies, plastics, andpolymers or copolymers of acrylic acid, methacrylic acid, esters ofthese acids, and acrylonitrile. Preferably, the film comprises amaterial selected from linear polyethylene, polyethylenes, plastics,polycarbonates, polyethylene terephthalate, and acrylics. Preferably,the second surface of the film is coated with a hydrophilic coating.Preferably, the lens substrate is between 0.1 to about 10 millimeters inthickness. Preferably, the lens substrate is between 1 to about 3millimeters in thickness. Preferably, the film is between 0.002 to about0.020 inches in thickness. Preferably, the film is between 0.007 toabout 0.010 inches in thickness. Preferably, the lens further includes ahard coat film having a first surface and a second surface, the firstsurface adjacent and substantially covering the outer surface of thelens. Preferably, the first surface of the hard coat film is bonded tothe outer surface of the lens during the molding process of the lens.Preferably, the hard coat film comprises a material selected from thegroup consisting of polyvinyl chloride, fluorocarbons, polyethylenes,polyethylene terephthalate, polyurethane prepolymer, polycarbonates,polystyrene, polypropylene, cellulosic resins, acrylic resins,acrylates, methyl methacrylate, polymethyl-methacrylate, epoxides,epoxies, plastics, and polymers or copolymers of acrylic acid,methacrylic acid, esters of these acids, and acrylonitrile.

These and other features, aspects, and advantages of the presentinvention will become better understood with regard to the followingdescription, appended claims, and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exploded view of a gauge with an embodiment of agauge lens with embedded anti-fog film of the present invention;

FIG. 2 illustrates a plan view of the gauge lens with embedded anti-fogfilm of FIG. 1 of the present invention;

FIG. 3 illustrates a cross-sectional view of the gauge lens withembedded anti-fog film of FIG. 2 through the lines 3-3 of the presentinvention;

FIG. 4 illustrates a detailed view of the gauge lens with embeddedanti-fog film at reference number 4 of FIG. 3 of the present invention;

FIG. 5 illustrates a plan view of another gauge lens with embeddedanti-fog film of the present invention;

FIG. 6 illustrates a cross-sectional view of the gauge lens withembedded anti-fog film of FIG. 5 through the lines 6-6 of the presentinvention;

FIG. 7 illustrates a detailed view of the gauge lens with embeddedanti-fog film at reference number 7 of FIG. 6 of the present invention;

FIG. 8 illustrates a plan view of another gauge lens with embeddedanti-fog film of the present invention;

FIG. 9 illustrates a cross-sectional view of the gauge lens withembedded anti-fog film of FIG. 8 through the lines 9-9 of the presentinvention;

FIG. 10 illustrates a detailed view of the gauge lens with embeddedanti-fog film at reference number 10 of FIG. 9 of the present invention;

FIG. 11 illustrates a plan view of another gauge lens with embeddedinner anti-fog film and outer hard coat film of the present invention;

FIG. 12 illustrates a cross-sectional view of the gauge lens withembedded inner anti-fog film and outer hard coat film of FIG. 11 throughthe lines 12-12 of the present invention;

FIG. 13 illustrates a detailed view of the gauge lens with embeddedinner anti-fog film and outer hard coat film at reference number 13 ofFIG. 12 of the present invention;

FIG. 14 illustrates an exploded view of another gauge with anotherembodiment of a gauge lens with embedded anti-fog film of the presentinvention;

FIG. 15 illustrates a plan view of the gauge lens with embedded anti-fogfilm of FIG. 14 of the present invention;

FIG. 16 illustrates a cross-sectional view of the gauge lens withembedded anti-fog film of FIG. 15 through the lines 16-16 of the presentinvention;

FIG. 17 illustrates a detailed view of the gauge lens with embeddedanti-fog film at reference number 17 of FIG. 16 of the presentinvention;

FIG. 18 illustrates a cross-sectional view of an embodiment of aninjection mold for producing the gauge lens with embedded anti-fog filmof FIG. 8 of the present invention;

FIG. 19 illustrates a cross-sectional view of an embodiment of aninjection mold for producing the gauge lens with embedded anti-fog filmof FIG. 5 of the present invention;

FIG. 20 illustrates a cross-sectional view of an embodiment of aninjection mold for producing the gauge lens with embedded anti-fog filmof FIG. 11 of the present invention;

FIG. 21 illustrates a cross-sectional view of an embodiment of aninjection mold without a peripheral lip for producing the gauge lenswith embedded anti-fog film of FIG. 11 of the present invention;

FIG. 22 illustrates process flow diagram for a gauge lens with embeddedanti-fog film of FIGS. 2, 5, 8, and 15; and

FIG. 23 illustrates another process flow diagram for a gauge lens withembedded anti-fog film of FIG. 11.

DETAILED DESCRIPTION OF THE DRAWINGS

In accordance with the present gauge lens with embedded anti-fog film(“gauge lens”), the gauge lens may be part of many different types ofsealed articles, including barometers, meters, instruments, instrumentclusters, instrument panels, goggles, glasses, or other such lensedarticles. The gauge lens is to be used with gauges for all vehicles thatare exposed to environmental conditions and moisture, such asall-terrain vehicles (ATV's), snowmobiles, motorcycles, and the like.Additionally, the gauge lens is also used with gauges that are exposedto environmental conditions that may not be part of vehicles, but arepart of instruments such as weather stations, and the like.

FIG. 1 illustrates an embodiment of the present gauge lens 100 and isshown as part of a gauge 102, which preferably includes a gauge housing104, a seal 108, and mechanical and electrical components 106. A seal108 preferably provides a watertight seal between the gauge lens 100 andthe gauge housing 104 when assembled, thereby preventing moisture fromentering the gauge 102 between the gauge housing 104 and the gauge lens100. The gauge housing 104 preferably includes slots 110 for acceptingtabs 122 (depicted in FIG. 2) of the gauge lens 100.

FIG. 2 illustrates the gauge lens 100, lens substrate 120, and aplurality of tabs 122 for mating with the corresponding slots 110 of thegauge housing 104 to connect or attach the gauge lens 100 to the gaugehousing 104 during assembly. Other fastening arrangements commonly knownmay also be employed to secure the gauge lens 100 to the gauge housing104. FIG. 3 illustrates a cross-section of the gauge lens 100 includingthe lens substrate 120 having a planar-shaped cross-section. The gaugelens 100 includes a sidewall 124 that extends annularly from the lenssubstrate 120 towards the gauge housing 104 that creates a cavity 126 ofthe gauge lens 100. The lens substrate 120 and sidewall 124 have aninner surface 128 that faces the cavity 126 of the inner of the gauge102 and an outer surface 130 that faces outwardly from the gauge 102. Ananti-fog film 132 is adjacent to the lens substrate 120 and preferablycovers the entire inner surface 128 of the lens substrate 120. The gaugelens 100 further includes ribs 134 for providing additional rigidity tothe gauge lens 100 and for securing some or all of the mechanical andelectrical components 106 of the gauge 102. These mechanical andelectrical components 106 typically include mechanisms, electronics,controls, and displays that are encapsulated or enclosed between thegauge lens and gauge housing when the gauge is assembled.

FIG. 4 illustrates a detailed view of the reference number 4 of FIG. 3showing the lens substrate 120 and sidewall 124 of the gauge lens 100.In this embodiment, the anti-fog film 132 can be seen having a firstsurface 136 that faces and is adjacent to the lens substrate 120 and asecond surface 138 that faces the cavity 126. In this embodiment, thelens substrate 120 has been molded so that the second surface 138 isflush with the inner surface 128 of the lens substrate 120 but does notwrap around to cover the inner surface 128 of the sidewall 124 of thegauge lens 100.

FIGS. 5 and 6 illustrate another embodiment 150 of the gauge lens wherethe anti-fog film 164 covers the inner surface 166 and a portion of thesidewall 168 of the lens substrate 160. As in FIG. 2, tabs 162 areprovided for engaging the slots 110 of the gauge housing 104. FIG. 6illustrates a cross-section of the gauge lens 150 including the lenssubstrate 160 having a planar-shaped cross-section. The gauge lens 150includes a sidewall 168 that extends annularly from the lens substrate160 towards the gauge housing 104 that creates a cavity 174 of the gaugelens 150. The anti-fog film 164 is adjacent to the lens substrate 160and preferably covers the entire inner surface 166 of the lens substrate160 and a portion of the inner surface 166 of the sidewall 168 of thegauge lens 150. Additionally, the gauge lens 150 further includes ribs172 for providing additional rigidity to the gauge lens 150 and forsecuring some or all of the mechanical and electrical components 106 ofthe gauge 102.

FIG. 7 illustrates a detailed view of the reference number 7 of FIG. 6showing the lens substrate 160 and sidewall 168 of the gauge lens 150.In this embodiment, the anti-fog film 164 can be seen having a firstsurface 176 that faces and is adjacent to the lens substrate 160 and asecond surface 178 that faces the cavity 174. In this embodiment, thelens substrate 160 and sidewall 168 have been molded so that the secondsurface 178 of the anti-fog film 164 is flush with the inner surface 166of the lens substrate 160 and does wrap around and is flush with aportion of the sidewall 168 of the lens substrate 160.

FIGS. 8 and 9 illustrate another embodiment 200 of the gauge lens wherethe anti-fog film 214 covers the inner surface 216 of the lens substrate210. As in FIG. 2, tabs 212 are provided for engaging the slots 110 ofthe gauge housing 104. FIG. 9 illustrates a cross-section of the gaugelens 200 including a lens substrate 210 having a planar-shapedcross-section. The anti-fog film 214 is adjacent to the lens substrate210 and preferably covers the entire inner surface 216 of the lenssubstrate 210. FIG. 10 illustrates a detailed view of the referencenumber 10 of FIG. 9 showing the lens substrate 210 and sidewall 218 ofthe gauge lens 200. In this embodiment, the anti-fog film 214 can beseen having a first surface 226 that faces and is adjacent to the lenssubstrate 210 and a second surface 228 that faces the cavity 224. Inthis embodiment, the anti-fog film 214 has been molded so that theanti-fog film 214 meets an inner peripheral rim 230 of the lenssubstrate 210.

FIGS. 11 and 12 illustrate another embodiment 250 of the gauge lenshaving an anti-fog film material 264 that covers the inner surface 272of the lens substrate 260 and a hard coat film 266 that covers the outersurface 284 of the lens substrate 260. As in FIG. 2, tabs 262 areprovided for engaging the slots 110 of the gauge housing 104. FIG. 12illustrates a cross-section of the gauge lens 250 including a lenssubstrate 260 having a planar-shaped cross-section. The anti-fog film264 is adjacent to the lens substrate 260 and preferably covers theentire inner surface 272 of the lens substrate 260 and a hard coat film266 that preferably covers the entire outer surface 286 of the lenssubstrate 260. FIG. 13 illustrates a detailed view of the referencenumber 13 of FIG. 12 showing the lens substrate 260 and sidewall 268 ofthe gauge lens 250. In this embodiment, the anti-fog film 264 can beseen having a first surface 274 that faces and is adjacent to the lenssubstrate 260 and a second surface 276 that faces the cavity 284. Inaddition, the hard coat film 266 can be seen having a first surface 280that faces and is adjacent to the outer surface 286 of the lenssubstrate 260 and a second surface 278 that faces away from the lenssubstrate 260. This embodiment provides for a durable lens substrate 260having an anti-fog film 264 molded to the inner surface 272 of the lenssubstrate 260 for providing anti-fog properties to the inner surface 272of the lens substrate 260 and sidewall 268 and an outer hard coat film266 for improved UV stability and durability to the outer surface 286 ofthe lens substrate 260.

FIG. 14 illustrates another embodiment of the present gauge lens 300 andis shown as part of an instrument panel 302, which preferably includesan instrument panel housing 306, and mechanical and electricalcomponents 308. FIGS. 15 illustrate the gauge lens 300 and lenssubstrate 310. FIG. 16 illustrates a cross-section of the gauge lens 300including the lens substrate 310 having a planar-shaped cross-section.An anti-fog film 312 is adjacent to the lens substrate 310 andpreferably covers the entire inner surface of the lens substrate 310.

FIG. 17 illustrates a detailed view of the reference number 17 of FIG.16 showing the lens substrate 310 and the anti-fog film 312 of the gaugelens 300. In this embodiment, the anti-fog film 312 can be seen having afirst surface 314 that faces and is adjacent to the lens substrate 310and a second surface 316 that faces the instrument panel housing 306.

In addition to being the cross-section being planar-shaped, lenssubstrates 110, 160, 210, and 260, and 310 can further be concave,convex, or dish-shaped depending on the desired application. In theseembodiments, the lens substrates 110, 160, 210, and 260 are depicted asbeing circular, however, they can be other symmetrical and asymmetricalshapes, as shown in lens substrate 310. The gauge housing and mechanicaland electrical components of the gauge described herein accept and workwith each of the various embodiments of gauge lenses described above.One of the mechanical features of typical gauges is a reset mechanism,thus one aspect of the lens substrates 110, 160, 210, 260, and 310 isthat they include a hole (not shown) where a mechanical stem or shaft(not shown) protrudes through to enable a user to reset some aspect ofthe gauge. A rubber enclosure (not shown) surrounds the stem or shaftand seals to the lens substrates 110, 160, 210, 260, and 310 forproviding waterproof operation of the reset mechanism. In addition, thegauge housing 104 and instrument panel housing 306 receive a wiringharness or group of wires through the gauge housing 104 necessary forsupplying electricity to the electronic devices within gauges 102 and302. The wiring harness generally plugs into the back of the gaugehousing 104 and instrument panel housing 306 and is sealed against thegauge housing 104 and instrument panel housing 306 for watertightoperation.

The materials for the lens substrates 110, 160, 210, 260, and 310 areselected from transparent, clear, and thermoplastic materials that arecapable of being heated and injected into a mold for forming the clearlens substrate. The material can be selected based upon certain criteriaregarding the operation of the gauge. For example, if the criteria forXenon arc weather ability test results is 200 hours as opposed to 1,000hours, but high impact resistance is required, then the material for thelens substrate 110, 160, 210, 260, and 310 can be a polycarbonate orother material that provides high impact resistance, but lower UVstability requirements. In addition, it is preferable that the materialsfor the lens substrates 110, 160, 210, 260, and 310 are thermoplastic,so that during the heating step of the manufacturing process, asdescribed below, the materials fluidize and are able to be injectedthrough an injector into the injection molds. These materials includepolyvinyl chloride, nylon, fluorocarbons, linear polyethylene,polyethylenes, polyethylene terephthalate, polyurethane prepolymer,polyesters, polycarbonates, polystyrene, polypropylene, cellulosicresins, acrylic resins, acrylates, methyl methacrylate,polymethyl-methacrylate, epoxides, epoxies, plastics, and polymers orcopolymers of acrylic acid, methacrylic acid, esters of these acids, andacrylonitrile. Some exemplary materials include polymethyl-methacrelate(PMMA) such as Asahi Kasei Delpet 80N and Cyro H15-002.

The materials for the anti-fog films 132, 164, 214, 264, and 312 areselected from transparent, clear films that are capable of withstandingthe temperatures of injection molding processes without distortion ofthe transparent properties. The materials are provided in thin sheetsthat possess an anti-fog coating or composition on at least one side ofthe thin sheet. In addition, the anti-fog films 132, 164, 214, 264, and312 are further selected based on their favorable bonding strength tothe lens substrates 110, 160, 210, 260, 310 during the mold injectionprocess. The material can be selected based upon certain criteriaregarding the operation of the gauge. The materials for the anti-fogfilms 132, 164, 214, 264, and 312 can be selected such that thecomposition of the anti-fog film 132, 164, 214, 264, and 312 itselfpossesses the anti-fog characteristics, or it can be a film that iscoated with an anti-fog or hydrophilic coating. In one aspect, thematerial or coating possesses hydrophilic properties and in anotheraspect the material or coating possesses hydrophobic properties.Preferably, the anti-fog coating would be on the second surfaces 138,178, 228, 276, and 316 of the anti-fog films 132, 164, 214, 264, and312.

Some examples of materials for anti-fog films 132, 164, 214, 264, and312 include but are not excluded linear polyethylene, polyethylenes,plastics, polycarbonates, polyethylene terephthalate, acrylics or otherclear material that possesses anti-fog properties and can be pressedinto sheets of desirable thicknesses and that bond favorably to theselected lens substrate material. In one aspect of the present gaugelens, the anti-fog film 132, 164, 214, 264, and 312 is a polycarbonatematerial coated with a hydrophilic coating. An exemplary materialincludes Lexan® HP FAF from General Electric.

As noted above, preferably a strong bond is created between the lenssubstrates 110, 160, 210, 260, and 310 and the anti-fog films 132, 164,214, 264, and 312. In one aspect of the present gauge lens, the lenssubstrate material is an acrylic and the anti-fog film is apolycarbonate, and in another the lens substrate material is apolycarbonate and the anti-fog film is a polycarbonate. In each of thesetwo non-limiting examples, a sufficient or adequate bond is formedbetween the two materials during the injection molding process.

The materials for the hard coat film 266 are selected from transparent,clear films that are capable of withstanding the temperatures ofinjection molding processes without distortion of the transparentproperties. The materials can be selected from those materials that arecapable of being produced in thin sheets, preferably formable and thatpossess a durable and UV-resistant coating or composition that providesprotection against UV-radiation and damage caused by operation of thegauge lens in its intended or desired environment. In addition, the hardcoat film 266 is further selected based on their favorable bondingstrength to the lens substrates 110, 160, 210, 260, 310 during the moldinjection process. The material can be selected based upon certaincriteria regarding the environment that the gauge will be operated in.

Some examples of materials for those hard coat film 266 includepolyvinyl chloride, fluorocarbons, polyethylenes, polyethyleneterephthalate, polyurethane prepolymer, polycarbonates, polystyrene,polypropylene, cellulosic resins, acrylic resins, acrylates, methylmethacrylate, polymethyl-methacrylate, epoxides, epoxies, plastics, andpolymers or copolymers of acrylic acid, methacrylic acid, esters ofthese acids, and acrylonitrile.

The thickness of the lens substrates 110, 160, 210, 260, and 310 isdependent upon the desired application of the gauge lens. Preferably thelens substrate thickness is between 1 and 20 millimeters, and morepreferably between 2 and 10 millimeters. The thickness of the anti-fogfilm 132, 164, 214, 264, and 312 is based on the design of the gaugelens. Preferably the anti-fog film thickness is between 0.002 and 0.020inches, and more preferably between 0.007 and 0.010 inches.

Shapes of the gauge lens 100, 150, 200, 250, and 300 may be symmetricalor asymmetrical depending on the desired design or application. Forexample, they may be a substantially planar-shaped lens having acircular shape, such as a 4-inch diameter round gauge lens that arecommonly found on ATV's and snowmobiles, such as that depicted in FIGS.1 and 2.

In addition to the aforementioned aspects and embodiments of the presentgauge lens 100, 150, 200, 250, and 300, the present invention furtherincludes methods for making these embodiments of the gauge lens 100,150, 200, 250, and 300.

Generally, the lens substrate 110, 160, 210, 260, and 310 and anti-fogfilm 132, 164, 214, 264, and 312 are bonded together during theinjection molding process. Typically, the anti-fog film 132, 164, 214,264, and 312 are cut, possibly shaped, and then positioned onto one halfof a typical injection mold as commonly found in the injection moldingart, such as those injection molds found in in-mold decoration (IMD)applications. The mold is then closed and then the lens substratematerial is fed into a machine that heats and then injects the materialinto the mold. Molds are designed and made to produce a finished moldedpart that is required or desired by the application at hand.

FIG. 18 illustrates a cross sectional view of one embodiment 350 of aninjection mold for producing the gauge lens 200. The mold 350 has a coreside 352 and a cavity side 354 for intermolding the anti-fog film 214against the lens substrate 210 to form the gauge lens 200. The mold 350includes a peripheral lip 230 encircling the outer perimeter of theupper part of the core side 352 for accepting and holding the anti-fogfilm 214 in place during injection of the lens substrate resin, throughgate 356, into the mold 350 to mold the gauge lens 200 including thelens substrate 210, sidewall 218 and anti-fog film 214.

FIG. 19 illustrates a cross sectional view of another embodiment 400 ofan injection mold for producing the gauge lens 150. The mold 400 has acore side 402 and a cavity side 404 for intermolding the anti-fog film164 against the lens substrate 160 to form the gauge lens 150. The coreside 402 accepts and holds a fitted, shaped, or thermofitted anti-fogfilm 164 in place during the injection of the lens substrate resin,through gate 406, into the mold 400 to mold the gauge lens 150 includingthe lens substrate 160, sidewall 168, and anti-fog film 164.

FIG. 20 illustrates a cross sectional view of another embodiment 450 ofan injection mold for producing the gauge lens 250. The mold 450 has acore side 452 and a cavity side 454 for intermolding the anti-fog film264 and the hard coat film 266 against the lens substrate 260 to formthe gauge lens 250. The mold 450 includes a peripheral lip 282, similarto that described in FIG. 13, encircling the outer perimeter of theupper part of the core side 452 for accepting and holding the anti-fogfilm 264 in place. Additionally, the hard coat film 266 is formed orshaped to enable it to fit snugly or be pressed into the cavity side454. Then lens substrate resin is injected, through gate 456, into themold 450 to mold the gauge lens 250 including the lens substrate 260,sidewall 268 anti-fog film 264, and hard coat film 266.

FIG. 21 illustrates a cross sectional view of another embodiment 500 ofan injection mold for producing the gauge lens 250. The mold 500 has acore side 502 and a cavity side 504 for intermolding the anti-fog film264 and the hard coat film 266 against the lens substrate 260 to formthe gauge lens 250. The core side 502 accepts a fitted, shaped, orthermoformed anti-fog film 164. Additionally, the hard coat film 266 isformed or shaped to enable it to fit snugly or be pressed into thecavity side 504. The lens substrate resin is injected, through gate 506,into the mold 500 to mold the gauge lens 250 including the lenssubstrate 260, sidewall 268 anti-fog film 264, and hard coat film 266.

The molds 350, 400, 450, and 500 may further include elements such asrecesses, cavities, and the like for retaining the anti-fog film 132,164, 214, 264, and 312 in the molds during the injection of the lenssubstrate resin material. Additionally, other means may be employedincluding applying a vacuum or static electricity to retain the anti-fogfilm 132, 164, 214, 264, and 312 in place in the mold during theinjection process.

Preferably, the anti-fog film 132, 164, 214, 264, and 312 is cut, by adie or other similar cutting tool, to a desired shape and then placed inthe mold prior to injecting the lens substrate resin. As describedabove, the anti-fog film can also be formed prior to inserting it intothe mold 400, 450, and 500 prior to injecting the lens substrate resinmaterial. In one aspect, this can be accomplished by heating theanti-fog film 164, 214, and 264 and forming it to a desired shape priorand then allowing the anti-fog film 164, 214, and 264 to cool to aformed shape. The cut and/or shaped anti-fog film 164, 214, and 264 isthen placed, positioned, or pressed into typically one half of an openmold 350, 400, 450, and 500 of a molding machine. These molding machinesare commonly used and can be arranged such that the molds are placed ona rotary table for inserting the anti-fog film 132, 164, 214, 264, and312. The molds 350, 400, 450, and 500 may also be cleaned, such as bycompressed air, prior to inserting the anti-fog film 132, 164, 214, 264,and 312 into the mold 350, 400, 450, and 500. After the anti-fog film132, 164, 214, 264, and 312 is placed or inserted into one half of themold, then the second half of the mold is typically closed down on topof the first half containing the anti-fog film 132, 164, 214, 264, and312 and then the lens substrate material resin is injected into themold. After injection of the resin, the material is then preferablycooled and then removed from the mold.

FIG. 22 illustrates an embodiment of a process 550 for manufacturing thegauge lens 100, 150, and 200. In step 552, the anti-fog film 132 and 214is cut to a desired size to fit the core side 352 of mold 350. If it isdetermined in step 554 that the anti-fog film 164 is to be used, thenanti-fog film 164 is shaped or formed in step 556 to fit the core side402 of mold 400. In step 558, the anti-fog film 132 and 214 ispositioned onto core side 352 of mold 350 and anti-fog film 164 ispositioned onto core side 402 of mold 400. Then in step 560, the mold350 and 400 are closed and prepared for heating and injection of thelens substrate resin material. In step 562, the mold 350 and 400 areheated and in step 564 the resin material that comprises the lenssubstrate 120 and 210 is injected into mold 350 and the resin materialthat comprises the lens substrate 160 is injected into mold 400. Thelens substrate 120, 160, and 210 material then is cooled in step 566 andlater removed in step 568 to provide a gauge lens 100, 150, and 200.

FIG. 23 illustrates another embodiment of a process 600 formanufacturing the gauge lens 250. In step 602, the anti-fog film 264 iscut to a desired size to fit the core side 452 of mold 450 and core side502 of mold 500. If it is determined in step 604 that the anti-fog film264 or hard coat film 266 is to be used, then it is shaped or formed instep 606. In step 606, the hard coat film 266 is formed to fit snuglyinto the cavity side 454 of mold 450. Also in step 606, the anti-fogfilm 264 and hard coat film 266 is formed to fit snugly into the coreside 502 and cavity side 504, respectively, of mold 500. In step 608,the anti-fog film 264 is positioned onto core side 452 and the hard coatfilm 266 is positioned onto the cavity side 454 of mold 450, and theanti-fog film 264 is positioned onto core side 502 and the hard coatfilm 266 is positioned onto cavity side 504 of mold 500. Then in step610, the mold 450 and 500 are closed and prepared for heating. In step612, the mold 450 and 500 are heated and in step 614 the resin materialthat comprises the lens substrate 260 is injected into mold 450 andresin material that comprises the lens substrate 260 is injected intomold 500. The lens substrate 260 material then is cooled in step 616 andlater removed in step 618 to provide a gauge lens 250.

In these molding methods necessary flash and part lines in addition tovents are employed to optimize the molding process and finish of thegauge lens 100, 150, 200, 250, and 300. Structural cross ribs areincorporated into the design of the gauge lens as needed for structuralstrength.

The temperature of the injector and mold during the molding process isselected based upon the materials present during the molding process.Preferably, the injection and molding temperature is between 100 and 600degrees Fahrenheit. Once the gauge lens 100, 150, 200, 250, and 300 ismolded and cooled, it may undergo further finishing steps, such asdeburring or removing mold seams and/or runners if necessary prior tobeing assembled to the gauge body 104.

Several different connection arrangements are provided, includingmolding small tabs 122, 212, 162, and 262 on the side of the gauge lens100, 150, 200, 250, and 300 that engage or snap into corresponding slots110 in the gauge body 104. In addition, commonly known mechanicalfixture devices can be used to assemble the gauge lens 100, 150, 200,250, and 300 to the gauge housing 104 and instrument panel housing 306,respectively. This interface of the gauge lens 100, 150, 200, 250, and300 and gauge body 104 and instrument panel housing 306 is preferablywaterproof. Rubber o-rings or seals, such as seal 108, can also beemployed between the interface of the gauge body 104, instrument panelhousing 306 and the gauge lens 100, 150, 200, 250, and 300 to provideadditional waterproofing properties.

EXAMPLE 1 Gauge Lens with Non-Formed Anti-Fog Film

A mold 350 was opened, cleaned, and prepared for forming gauge lens 200.The mold 350 provided for a 1.8 mm thickness sidewall 218 and lenssubstrate 210. A 0.007 inch film of polycarbonate anti-fog film 214,Lexan® HP FAF produced by General Electric, was cut in a circular shapehaving a 4 inch diameter and positioned with the second surface 228facing the core side 352 of mold 350. The mold 350 was then closed andattached to a nozzle of a heated screw injector. An acrylic polymer lenssubstrate 210 material, Acrylite Cyro H15-002, was placed into a hopperof the heated screw injector and then heated to 250° C. and injectedinto the mold 350. The mold 350 was allowed to cool to room temperatureand the gauge lens 200 was removed and cleaned of molding seams orrunners. The gauge lens 200 was subjected to Xenon arc light test ASTM G155 and tested for 1000 hours with no notice of de-lamination betweenthe lens substrate 210 and the anti-fog film 214. In addition, no lossof anti-fog properties and no significant yellowing or degradation ofthe lens substrate 210 and anti-fog film 214 were noted. The gauge lens200 was subjected to thermal shock of 100 cycles between +90° C. and−40° C. with no notice of de-lamination between the lens substrate 210and the anti-fog film 214. Further, no loss of anti-fog properties werenoted. The gauge lens 200 was then subjected to drop tests, byrepeatedly dropping the lens substrate 200 from a distance of 3 metersfrom a concrete floor onto on each of 6 axes (+/−x, +/−y, +/−z,) with nodamage or de-lamination noticed between the lens substrate 210 andanti-fog film 214.

Although there has been described what is at present considered to bethe preferred embodiments of the present gauge lens with anti-fog film,it will be understood that the gauge lens can be embodied in otherspecific forms without departing from the spirit or essentialcharacteristics thereof. For example, additional means, other than thosedescribed herein, for retaining the anti-fog film to the mold during theinjection process may be used. Also, other injection mold arrangementsmay be used other than those described herein without departing from theinventive novelty described herein. The present embodiments are,therefore, to be considered in all aspects as illustrative and notrestrictive. The scope of the invention is indicated by the appendedclaims rather than the foregoing description.

1. A lens having anti-fog properties for use with a gauge body,comprising: a substantially planar transparent lens substrateterminating at its periphery in a sidewall, said lens substrate and saidsidewall having an outer surface and an inner surface; and a film havinga first surface and a second surface, said first surface of said film isadjacent and substantially covering said inner surface of said lens, andsaid second surface providing a water wettability of less than about 10°in terms of contact angle for preventing moisture condensation fromforming on said second surface of said film, wherein said first surfaceof said film is bonded to said inner surface of said lens during themolding process of said lens by heating a mold in which the film isplaced.
 2. The lens of claim 1, wherein said first surface of said filmcovers a portion of said inner surface of said sidewall.
 3. The lens ofclaim 2, wherein said first surface of said film is bonded to a portionof said inner surface of said sidewall during the molding process ofsaid lens.
 4. The lens of claim 1, wherein said lens substrate comprisesa thermoplastic material.
 5. The lens of claim 1, wherein said lenssubstrate comprises a polymer selected from the group consisting ofpolyvinyl chloride, nylon, fluorocarbons, linear polyethylene,polyethylenes, polyethylene terephthalate, polyurethane prepolymer,polyesters, polycarbonates, polystyrene, polypropylene, cellulosicresins, acrylic resins, acrylates, methyl methacrylate,polymethyl-methacrylate, epoxides, epoxies, plastics, and polymers orcopolymers of acrylic acid, methacrylic acid, esters of these acids, andacrylonitrile.
 6. The lens of claim 1, wherein said film comprises amaterial selected from linear polyethylene, polyethylenes, plastics,polycarbonates, polyethylene terephthalate, and acrylics.
 7. The lens ofclaim 1, wherein said second surface of said film is coated with ahydrophilic coating.
 8. The lens of claim 1, wherein said second surfaceof said film is coated with a hydrophobic coating.
 9. The lens of claim1, further comprising a hard coat film having a first surface and asecond surface, said first surface adjacent and substantially coveringsaid outer surface of said lens.